Isometric Resistance Training and Remote Ischaemic Conditioning as Adjunct Therapies for Hypertension

Abstract

<p><b>Background</b></p><p>Hypertension remains a cardiovascular disease (CVD) risk factor and is the leading cause of morbidity and mortality globally. Maintaining optimal blood pressure (BP) is important for CVD prevention and treatment. Recommended hypertension treatment includes both pharmacological and non-pharmacological interventions. Non-pharmacological interventions, or lifestyle modifications, such as exercise training, have varied approaches and long-term adherence is challenging. A growing interest in non-pharmacologic approaches necessitates alternative anti-hypertensive interventions. In this thesis the primary aim was to evaluate isometric resistance training (IRT) and remote ischaemic conditioning (RIC) as potential adjunct therapies for hypertension. </p> <p><b>Methods</b></p> <p>Systematic reviews and meta-analyses were undertaken to evaluate 1) the benefits and risks of intensive versus standard BP treatment targets in older adults with hypertension; 2) the effect of exercise training on the renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system (SNS) activity as these relate to BP changes; 3) the efficacy of IRT for hypertension management; and 4) the magnitude of RIC effects on BP. A modified Delphi technique was employed to seek expert opinion on the safety, efficacy, programming, delivery and mechanisms of action of IRT as an adjunct anti-hypertensive therapy. Finally, findings from these works were used to outline an evidence-based guide on the efficacy, safety and delivery of IRT.</p> <p><b>Results</b></p> <p>The major findings from the systematic reviews and meta-analyses demonstrated that 1) Lower BP treatment targets significantly reduced the relative risk of major cardiovascular events and all-cause mortality; 2) Exercise training produced significant reductions in BP, mediated via changed angiotensin-II and aldosterone concentrations, both key mediators of RAAS; 3) IRT significantly lowered both office and night-time ambulatory BP; and 4) Repeated, but not acute, RIC produced clinically meaningful reductions in BP. The Delphi analysis showed expert consensus for the efficacy of IRT as an anti-hypertensive therapy, but some concerns remained regarding safety and optimal delivery of leg IRT.</p> <p><b>Conclusion</b></p> <p>This thesis identified IRT and RIC as simple and cost-effective anti-hypertensive therapies that can be achieved with minimal commitment. Repeat RIC seems promising, especially for unconditioned people who are unable to complete exercise training. The limited number studies evaluating RIC for hypertension management, however, tempered the recommendation of RIC as an adjunct anti-hypertensive therapy. The findings confirmed IRT as a potential adjunct anti- hypertensive therapy; IRT may produce similar effects to one antihypertensive medication and can be used as an alternative for those who cannot perform conventional exercise training. The evidence-based guide substantiated this and provides practical guidance on prescription and delivery of IRT.</p>